Now that I've presented the argument for atheism being maladaptive, certainly a very strong indication that there's something wrong with the idea, it's important to establish that I don't really classify atheism as a biological maladaptation. I have good reasons to believe it isn't, though I don't see how many of the most popular atheists, especially those who work in and around evolutionary biology could hold that it is anything but one. That's especially true of those who have pushed the idea that religious belief is a biological trait, as Sheldrake mentions. Dawkins, Dennett, even a lot of those with an even more tenuous attachment to actual science are the ones who put the question into that rather artificial form of categorization.
Atheism isn't like some genetic illness that leads to people dying before they reach reproductive maturity or reduce reproductive potential. I don't for one second believe that there is any such thing as a genetic foundation for religious belief or a belief in atheism, you can go from one to the other without any mutation in any gene leading to that. Given the somewhat popular line some atheists regurgitate, that all people are born atheists, you would think they could take the tiny intellectual baby step to the conclusion that the fact most people become religious precludes a genetic explanation. Though such a minor intellectual achievement would seem to be beyond the reach of even some of what are generally considered to be among the most sophisticated atheist intellectuals we have around today.
Considering their use of Charles Darwin in their promotional propaganda, it is a rather wonderful irony that their hero also provides the means to identify atheism as a maladaptive habit of thought, one that, if widely adopted, could be expected to lead to the extinction of any group, nation or species which adopted it. As I said I wouldn't do so but, then, I'm rather skeptical about natural selection being a real thing of the type which sets up that form of categorization. I certainly don't see how natural selection can be relevant to the question, though I'd certainly be open to having an explanation of how it could be from someone more competent to do so than Dawkins or Dennett. I'd love to talk to Rupert Sheldrake about that. You're more likely to get a polite and well reasoned explanation of his thoughts on the matter, with little danger of being ridiculed. Ridicule is such a dead give-away of a shaky intellectual position.